Halvorsen is getting hit harder than most pitchers
The simulator expects 0.543 bases allowed per batter faced against him — better than 5th percentile of qualified pitchers. The soft spot is Command (8th percentile). Short relief stints inflate strikeout rates a touch, so read the Strikeouts spoke with that in mind.
Each spoke is a skill estimate adjusted for sample size (not raw season stats), so farther out = better.
Percentiles vs. 424 qualified pitchers — 100+ batters faced, starters and relievers pooled. He hasn't reached that bar himself, so he is measured against them rather than counted among them.
96 batters faced · data through 2026-07-29.
Plays like…
Same archetype, nearest by rate — the pitchers whose profile looks most like this one.
Two skills separate pitching styles: finishing hitters without free passes (strikeout rate minus walk rate, right = better) and keeping the contact they do allow soft (hard-hit rate against, up = better).
Every dot is a qualified pitcher this season; dot size tracks batters faced. Click any dot to open that pitcher's page.
Dashed lines mark the league median on each skill.
Seth Halvorsen
League
Percentile
Bases per ball in play(fewer = better)
.630
.529
5th
Walk rate(fewer = better)
14%
9%
8th
Strikeout rate(higher = better)
19%
22%
28th
100th percentile = best in MLB.
Arsenal
What he throws, and what it does
Seth Halvorsen leans on his four-seam fastball (63% of pitches). His slider has performed closest to league average, with a 43% whiff rate.
Pitch mix & swing-and-miss
What they throw, how hard, and what misses bats — from pitch tracking, regular season only.
▼ −5 bases worse than a replacement arm this season
allowed 54 bases vs a replacement arm's 49 over the same batters faced
Results
All pitches
cost 2.2 per 1007.7 cost across 345
replacement
Four-Seam Fastball
63%↑ +8 pts vs '25
98.8 mph · lg 95.1↓ −1.2 mph vs '25
12% whiffs · lg 18%
cost 3.1 per 1007.4 cost across 235
Slider
29%↑ +9 pts vs '25
86.2 mph · lg 86.9↓ −3.3 mph vs '25
43% whiffs · lg 32%
cost 0.2 per 1000.3 cost across 110
Splitter
8%↓ −18 pts vs '25
90.2 mph · lg 86.8↓ −0.6 mph vs '25
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Mix by batter side
How the mix shifts against lefty and righty bats. Overall results by batter side are under Platoon splits.
Four-Seam Fastball
66% vs LHH
61% vs RHH
Slider
24% vs LHH
34% vs RHH
By appearance
How the stuff has held up outing to outing
One point per outing — how his velocity, movement, and pitch mix have moved across the season, with league context for scale. Each pitch keeps the same color in every chart.
Platoon splits
How he fares against lefties and righties
Platoon splits (EB/PA allowed)
Dot = shrunk true-talent estimate; bar = 50% probable range. Tap or hover any mark for its number, or tab to a row for all of them.
Faint diamond = his raw, unshrunk rate against that side — small samples make it noisy, which is why the model pulls the dot toward a more trustworthy estimate.
These are bases allowed, so lower is better. Weighted by how often he faces each side, the two splits average back to his modeled overall EB/PA allowed — not the xEB/PA headline at the top of the page, which folds in strikeouts and walks differently.
Gray tick (marked “lg”) = league median vs that side; the faint gray band behind it spans the middle half of the league (25th–75th percentile).
Shrunk splits beat raw splits on held-out seasons, most decisively at low batters-faced counts (relievers especially), and converge with the raw numbers as exposure builds.
vs LHB40 PA0.574
vs LHB: shrunk estimate 0.574 EB/PA, 50% probable range 0.553 to 0.597, based on 40 plate appearances. Raw (unshrunk) rate: 0.604 EB/PA. League median vs LHB: 0.422 EB/PA.
lg
vs RHB56 PA0.533
vs RHB: shrunk estimate 0.533 EB/PA, 50% probable range 0.509 to 0.554, based on 56 plate appearances. Raw (unshrunk) rate: 0.557 EB/PA. League median vs RHB: 0.406 EB/PA.
lg
0.3830.4420.5010.5600.620
← better (fewer bases allowed)worse →
Better vs RHB than vs LHB by 0.041 EB/PA allowed (modeled).
50% probable range: +0.034 to +0.049
About the typical split for a righty arm (median 0.041). He allows more than the league median against both sides.
Contact allowed
What hitters do when they connect
Batters go to the pull side off him most often, but the hardest contact goes up the middle.
Pull and oppo are relative to each batter's stance, so this pools all the hitters he faced.
Batted balls allowed
Where every ball hit off Seth Halvorsen landed this season.
Dots are colored by estimated bases (EB) — pale slate (easy out) to dark teal (home-run territory).
Filled dots are hits; hollow rings are outs — a dark ring in the outfield is a crushed ball his defense ran down.
Tap or hover a dot or a row to link the two; use the ▶ links below to watch on Baseball Savant.
Every ball in play is worth the bases its exit velocity and direction usually earn. Comparing those earned bases with the bases batters were actually credited shows whether his results have been lucky, unlucky, or fair.
Earned off his contact allowed40
Actually credited to batters37
Results have matched the contact quality — batters have been credited about what they earned off Seth Halvorsen.
over 64 balls in play · walks and strikeouts excluded on both sides
ERA 4.74 · WHIP 1.95 · BABIP against 0.311 (lg 0.288)
Best games
His biggest outings this year
Best games
His best outings this season by bases saved vs a replacement arm.
